BackgroundThe early identification of patients with acute inferior ST-segment elevation myocardial infarction (STEMI) with high risk features is particularly important. Acute inferior STEMI may be associated with ST-segment depression in the left precordial leads (V4–V6). This study assessed prognostic value of ST-segment depression in these left precordial leads during the admission of patients with acute inferior STEMI treated with primary percutaneous coronary intervention.MethodsThis retrospective study enrolled 1,374 patients with acute inferior STEMI who underwent primary percutaneous coronary angioplasty between March 2011 and June 2014. The patients were divided into two groups: one group (n = 687) with left precordial ST-segment depression and the other (n = 687) without such ST-segment changes.ResultsThe patients with left precordial ST-segment depression were older and had higher incidence of hypertension, diabetes mellitus, and higher levels of troponin. In-hospital mortality was higher in patients with left precordial ST-segment depression. Advanced coronary artery disease was more observed in these patients.ConclusionIn patients with acute inferior STEMI treated with primary coronary intervention, left precordial ST-segment depression during admission of ECG is associated with more advanced coronary artery disease, and worse in-hospital clinical outcomes.